In an active year of merger-and-acquisition activity in the region’s health-care industry, no deal had more twists and turns than Teva Pharmaceutical Industries’ $6.8 billion purchase of Cephalon Inc.— previously the region’s largest independent biotechnology company.

Teva, the world’s largest generic drug company looking to expand its presence in the branded and specialty drug segments, emerged as Cephalon’s white knight after the company became the target of a hostile takeover bid by Valeant Pharmaceuticals International Inc. of Canada, which put forth an unsolicited $5.7 billion.